Some substrates such as electrical wire or cable are overbraided with wire to provide electrical shielding and other substrates such as hydraulic hoses are overbraided with wire or other materials to provide increased strength characteristics. In both instances the overbraiding can also provide increased abrasion resistance and durability for the product. However, in many instances it is impractical to overbraid such substrates with a desired exterior material. For example, electrical wires and cables are frequently installed in computer installations and particularly robotic installations wherein it is desirable to bundle a number of wires or cables together and retrofit an abrasion resistant flexible sleeving over the wire or cable bundle at the time of installation or some time after the original installation. In other circumstances it is desirable to protect other conduits such as air, water or other hoses from abrasion by retrofitting abrasion resistant sleeving over the hose at the time of installation or thereafter.
Braided tubular sleeving has conventionally been used as field installed protective sleeving. One such product is the EXPANDO self-fitting protective oversleeve made by Bentley-Harris Manufacturing Co., Lionville, Pennsylvania. The EXPANDO sleeving is a braided tubular product made from a resilient engineering plastic yarn such as a monofilament polyester. The EXPANDO oversleeve is particularly well suited for field installation over wire and cable bundles or harnesses, hoses, and the like because the sleeving has an open weave construction which enables the braided tube to expand to three times it original diameter when the braided tube is axially compressed. When the axial compression is released the braided tube tends to return to its original smaller diameter due to the resilient nature of the engineering plastic yarn from which it is braided. This "springback" property gives the braided sleeving the desirable characteristic of being self-fitting and conforming to any size substrate which is larger than the original diameter of the sleeve and to any irregular shape of wire and cable bundle. Once installed on the substrate the braided sleeving tends to remain tightly conformed to the exterior of the substrate. Since the braided open weave construction of the oversleeving is very flexible, the oversleeving easily conforms to any bending and flexing of the substrate thus providing continual abrasion protection for the substrate.
The engineering plastics from which the braided oversleeving has been made provides more than an adequate degree of abrasion resistance in most applications. However, it is desirable in some applications to have a higher degree of abrasion resistance. Therefore it is an objective of this invention to provide a braided tubular oversleeving which has increased abrasion resistance while retaining the springback properties desirable for such oversleeving.